Hide glue gives you those toasted wheat underpinnings; must be true, I read it on UMGF
Bolt-on necks are the work of Satan-apparently...
In all seriousness though I have owned great-sounding instruments with various neck joints. All were chosen because of their tones and not the building method. Also, how can a couple of microns thickness of glue-assuming a very accurately cut dovetail-have an effect on tone? There aren't great gobs of the stuff in there-especially given the amount that gets squeezed out when the neck is fitted.